journalctl -b | grep zfs Created slice system-zfs\x2dimport.slice - Slice /system/zfs-import. systemd-udev-settle.service is deprecated. Please fix zfs-import-scan.service, zfs-import-cache.service not to pull it in. Starting zfs-import@backup.service - Import ZFS pool backup... Finished zfs-import@backup.service - Import ZFS pool backup. Starting zfs-import-cache.service - Import ZFS pools by cache file... zfs-import-scan.service - Import ZFS pools by device scanning was skipped because of an unmet condition check (ConditionFileNotEmpty=!/etc/zfs/zpool.cache). Finished zfs-import-cache.service - Import ZFS pools by cache file. Reached target zfs-import.target - ZFS pool import target. Starting zfs-mount.service - Mount ZFS filesystems... Starting zfs-volume-wait.service - Wait for ZFS Volume (zvol) links in /dev... Finished zfs-volume-wait.service - Wait for ZFS Volume (zvol) links in /dev. Reached target zfs-volumes.target - ZFS volumes are ready. Finished zfs-mount.service - Mount ZFS filesystems.
Solution:
systemctl enable zfs-import@backup2
Add rootdelay=20 to /etc/default/grub
and regenerate grub config:
proxmox-boot-tool refresh
Force pools to use /etc/zfs/zpool.cache file:
zpool import backup2 zpool set cachefile=/etc/zfs/zpool.cache backup zpool set cachefile=/etc/zfs/zpool.cache backup2 zpool get cachefile update-initramfs -k all -u reboot